Electron beam induced deposition at elevated temperatures: compositional changes and purity improvement

Thermally assisted electron beam induced deposition can result in an improvement of the purity of nano-scale depositions. Six commonly used organic precursors were examined: W(CO)6, TEOS (tetraethylorthosilicate), MeCpPtMe3, Co(CO)3NO, Co2(CO)8, and Me2Auacac. The last two precursors were also tested on two different instruments to confirm reproducibility of the results. The influence of the substrate temperature on the composition of the deposition has been quantified systematically in the temperature range 25-360 deg. C. It has been shown that most purities improve when applying an elevated temperature, while the shape of the deposition remains intact. The purity improvement is achieved at the cost of a lower deposition yield. The amount of improvement is different for each precursor. Within the maximum temperature range of 360 deg. C, the best improvement was found for W(CO)6: from 36.7 at.% at 25 deg. C to 59.2 at.% at 280 deg. C. For both cobalt precursors an additional transition region between patterned electron beam induced deposition (EBID) and thermal thin film growth has been identified. In this region seeded growth occurs with strongly increased growth rates.